Background and objectives: Several advantages can theoretically favor the use of normothermic perfusion, including the shortened duration of CPB, and simplification of the CPB management, it has been proposed as a more physiologic technique than hypothermic bypass for the maintenance of the body during cardiac surgery; we design a Prospective Randomized study to compare both approaches in terms of early myocardial protection.Methodology: Fifty patients who had mitral valve surgery in our institute were prospectively divided into two groups: Group I (n=25) received intermittent antegrade cold crystalloid cardioplegia with systemic hypothermia, and Group II (n=25) received intermittent antegrade warm blood cardioplegia. Clinical and metabolic studies have been carried to evaluate the efficacy of myocardial protection in both groups.Results: No differences were found between the two groups as regards the mortality, intubation time, total ICU stay time and the duration of inotropic support post operatively. However, the hypothermic group needed more defibrillation in the reperfusion period, more inotropic support to wean off bypass, and had more chest tube drainage. There was no difference in the postoperative level of CK and CK-MB between the two groups; however troponin I release was higher in the cold group. There was also no difference in the ventricular performance at follow up.Conclusion: Intermittent antegrade warm blood cardioplegia results in less myocardial cell damage than cold crystalloid cardioplegia, as assessed by the release of cardiac-specific markers. Better right ventricular preservation is possible but does not result in less need for inotropic support and consider a safe alternative to the standard intermittent antegrade cold blood cardioplegia.